Field of the Invention
The field of the invention is data processing, or, more specifically, methods, apparatus, and products for migrating MMIO.
Description of Related Art
A logical partition may be configured to utilize a physical, rather than virtual, I/O adapter. Such a configuration may rely on direct memory access operations between the I/O adapter. In current server-class systems there are large I/O fabrics incorporating many layers of bridge chips, switches, and I/O devices. The I/O devices themselves may be further virtualized in technologies such as SR-IOV. A memory mapped I/O (MMIO) access request generated by a logical partition must properly traverse this fabric and be delivered to the I/O device.
The routing and handling of the MMIO accesses involve both hardware configuration and software configuration across many layers of the system including the hypervisor and the logical partition. The logical partition is made directly aware of the MMIO address mappings which are associated with specific I/O devices. Any changes to these relationships require the updated configuration mappings to be communicated across all parties. This limits both configuration flexibility and the ability to reconfigure (for example, due to hardware failure or resource movement).